Slate is a fine-grained, foliated, homogeneous, metamorphic rock derived from an original shale-type sedimentary rock composed of clay or volcanic ash through low grade regional metamorphism. The result is a foliated rock in which the foliation may not correspond to the original sedimentary layering. Slate is frequently grey in colour especially when seen en masse covering roofs. However, slate occurs in a variety of colours even from a single locality. For example slate from North Wales can be found in many shades of grey from pale to dark and may also be purple, green or cyan.

Chemical composition

Uses of slate

Slate can be made into roofing slates, also called roofing shingles, installed by a slater in the USA. Slate has two lines of breakability: cleavage and grain. This makes it possible to split slate into thin sheets. Fine slate can also be used as a whetstone to hone knives. Due to its thermal stability and chemical inertness, slate has been used for laboratory bench tops and for billiard table tops. In 18th and 19th century schools, slate was extensively used for blackboards and individual writing slates for which chalk pencils were used. Because it is a good electrical insulator and fireproof, it was used to construct early 20th century electric switchboards and relay controls for large electric motors. British sculptor Stephen Kettle is notable for his use of slate to create statues housed in the Science Museum in London.

Slate tiles are often used for interior and exterior flooring or wall cladding. Tiles are installed and set on mortar and grouted along the edges. Chemical sealants are often used on tiles to improve durability and appearance, increase stain resistance, reduce efflorescence, and increase or reduce surface smoothness. Tiles are often sold gauged, meaning that the back surface is ground for ease of installation.

Slate tiles were used in 19th century UK building construction (apart from roofs). They can be set into the walls to provide a rudimentary damp-proof membrane. Small offcuts are used as shims to level floor joists.

Slate is often used as a decor in freshwater aquariums. Slate will not alter the chemistry of water (except in the slate containing feldspar which may leach silicates into the water resulting in excess diatom growth in marine aquaria). When broken, slate produces a natural appearance while remaining relatively flat and can be easily stacked. Silicone glue adheres to slate, creating a non-toxic bond to secure it. It is also used in stairs and pathways for the same reasons.

Traditional Japanese Go equipment uses slate for the black pieces.

Slate extraction

Slate-producing regions in Europe include Wales (see slate industry in Wales), Cornwall (famously the town of Delabole), and Cumbria (see Burlington Slate Quarries, Honister Slate Mine and Skiddaw Slate) in the United Kingdom; parts of France (Angers, Anjou and in the Maritime Alps); Belgium (formerly); Liguria in northern Italy especially between the town of Lavagna (which means chalkboard in Italian) and Fontanabuona valley; Portugal especially around Valongo in the north of the country; Germany's (Moselle River-region, Hunsrück, Eifel, Westerwald, Thuringia and north-Bavaria); Alta, Norway (actually schist not a true slate) and Galicia. In the Americas, slate is found in Brazil (the second biggest producer of slate) around Papagaio in Minas Gerais (responsible for 95% of the extraction of slate in Brazil), the east coast of Newfoundland, the Slate Belt of Eastern Pennsylvania, and the Slate Valley of Vermont and New York. The area around Granville, NY, is one place where colored slate (non-blue) is mined. Others include Wales (purple and formerly green) and Cumbria (green) in the UK; Brazil (green); China (many colors); and Newfoundland.

There was also a major slating operation in Monson, Maine during the late 19th and early 20th centuries. The slate found in Monson is usually a dark purple to blackish color, and many local structures are still roofed with slate tiles. Of many operations there is only one business currently operating. The output was so great it formed a train route throughout the woods of Monson and as many as 18 quarries were made. St. Patricks's Cathedral in New York's roof was made from roofing slate from Monson, as well as the Headstone of John F. Kennedy.

Slate is also found in the Arctic and was used by the Inuit to make the blades for ulus. China has vast slate deposits; in recent years its export of finished and unfinished slate has increased.

See also

• List of rock types
• Tile
• National Slate Museum
• Fell Exhibition Slate Mine
• Slate industry in Wales

External links

• AditNow - Photographic database of mines
• History of the Welsh slate industry
• John T F Turner - A Familiar Description of the Old Delabole Slate Quarries, 1864
• History of the Scottish Slate Islands
• Granville Slate Museum

SLATE, a pioneer organization of the New Left and precursor of the Free Speech Movement, was a campus political party at the University of California, Berkeley from 1958 to 1966.

Origins

The University of California, Berkeley, had a substantial tradition of student political activism ranging from peace agitation in the 1930s to resisting McCarthyism during the loyalty oath controversy of the 1950s. The first stirrings of the African-American Civil Rights Movement in the mid-1950s prompted a challenge by Ralph Shaffer, graduate student representative on the Associated Students of the University of California board, to discriminatory practices of fraternities and sororities. In 1957 a campus political party called Toward An Active Student Community (TASC) was organized by Fritjof Thygeson, Rick White and others. It ran candidates in the student government election. Its requirement that candidates be accountable to TASC, based on the British parliamentary system, was fiercely attacked in the Daily Californian (UCB's student newspaper). TASC's candidates ran on a liberal platform, and were substantially defeated. The next semester, Mike Miller, an undergraduate representative on the Associated Students Board, resigned and organized a slate of candidates to run on a platform supporting racial equality, free speech on campus, voluntary ROTC, and participation in the National Student Association. They doubled the electorate and received between 35-40% of the vote. Encouraged, the candidates, joined by Thygeson, White, Peter Franck, Marv Sternberg, and Wilson Carey McWilliams, formally established SLATE as a campus political party in February 1958 (the name was not an acronym, but simply stood for a slate of candidates who ran on a common platform). The university administration approved SLATE as a student organization, but not as a political party.

In the spring of 1959 the first and only SLATE student body president, David Armor, was elected, along with four other representatives, with strong support from graduate students. The university administration quickly responded by announcing that graduate students would no longer be considered members of the Associated Students and thus would be ineligible to vote in the student elections. SLATE continued to contest student elections, raising issues of free speech and academic freedom, as well as the right of students to take positions on such “off-campus” public issues as racial discrimination, capital punishment, civil liberties, war and peace, and farm worker organizing. Over the course of 1959 Berkeley Chancellor Clark Kerr developed a set of directives governing the rights of student organizations to sponsor speakers and prohibiting taking stands on “off-campus” issues. SLATE led the opposition to the Kerr Directives.

SLATE took positions on a number of controversial public issues that emerged in its first years. It supported a Berkeley fair housing ordinance in 1959, opposed the hearings conducted by the House Un-American Activities Committee (HUAC) in San Francisco in May 1960, supported the national Woolworth-Kress boycott called by civil rights organizations, opposed the execution of Caryl Chessman at San Quentin, and opposed continued nuclear weapon testing. SLATE also continued its advocacy for on-campus issues, including an end to compulsory ROTC, elimination of the Communist speaker ban, academic freedom, the rights of student organizations, and an idealistic critique of Kerr’s instrumental vision of the modern University. Articulating these positions were Ken Cloke and Michael Tigar, two SLATE representatives elected to the Associated Students board in the early 1960s.

SLATE served as an umbrella group for students whose politics ranged from Young Democrats to Trotskyist, and never became the exclusive possession of any one political sect or grouping. As Mike Miller put it, SLATE followed a politics of the “lowest significant common denominator,” in maintaining a multi-issue student organization committed to democracy, human rights, and peace. As word of students protests at Berkeley spread, campus political parties were organized at a number of American universities, including San Francisco State, Michigan, Iowa, UCLA, Riverside, Chicago, and Illinois.

Banned from campus

Public reaction to UC students participating in the demonstrations against HUAC, pickets against discrimination, and vigils against capital punishment was putting pressure on UC Regents and administrators. As SLATE continued to insist on the right to take stands on “off-campus issues,” the university administration responded by banning SLATE from the campus (the ban was later reversed).

Beginning in 1960 and continuing for four years, SLATE sponsored a series of summer conferences. The 1962 SLATE summer conference, “The Negro in America,” featured Charles McDew, chairman of the Student Non-Violent Coordinating Committee, and led to the formation of Bay Area Friends of SNCC. The 1963 SLATE summer conference, “Education in the Multiversity,” criticized Clark Kerr’s vision of the university, the role of universities in the Cold War, and argued for an expanded concept of student rights and academic freedom in university reform. As one of its educational reform projects, in fall 1963 SLATE began publishing The SLATE Supplement to the General Catalogue, evaluating campus departments, courses and instructors.

Impact of the FSM

In fall 1964, the issue SLATE had promoted since its founding, the right of student groups to give support to off-campus causes, came to a head over the right of students to place tables at the entrance of the campus to solicit members and contributions for a variety of issues. Leading the defense of these rights were a number of students who had been to Mississippi for Freedom Summer, or were otherwise involved with civil rights protests in the Bay Area. The Free Speech Movement that emerged from the University’s attempt to arrest and expel students who led the protests was even broader than SLATE’s coalition, as the FSM included Young Republicans and supporters of Barry Goldwater for President in the 1964 election. SLATE members were active in the FSM, but in general were not the leaders. SLATE won five positions on the Associated Students in the fall 1964 election, but failed to take over the student government when it only elected two representatives in Spring 1965, and lost the campaign for student body president as well. SLATE then attempted to draft a new student government constitution, but the proposed document was voted down in a referendum in April 1966. With many students feeling that student government was a hopeless arena for change, SLATE voted to dissolve itself in October 1966.

Reunions

The first reunion, attended by some 150 former SLATE members (out of an estimated 850 one-time card-carrying, dues-paying members), was held at the Berkeley campus in June 1984 with considerable media attention. A survey revealed that most who attended were still active in left-of-center politics, although there were exceptions. David Armor, SLATE’s only student body president (who did not attend), had made an unsuccessful run for a Los Angeles Congressional district in 1982 as a Reagan Republican, and Rick White, who did attend, found his neoconservative views treated respectfully but not shared. In an emotional session, SLATE women recalled the sexism they had encountered from male leaders in the organization. Two former SLATE members in attendance had achieved success in California electoral politics: Jackie Goldberg served on the Los Angeles school board and city council (and would later serve in the California Assembly from 2002 to 2006), and Bill Lockyer was then in the midst of his 25 years in California State Legislature, and would go on to serve as Attorney General of California (from 1999 to 2006) and state Treasurer (2007 to date). A second SLATE reunion was held in 2000 at a retreat center, and a third half-day reunion was held in conjunction with the 40th anniversary reunion of the FSM in 2004.

Notes

References

• Kenneth Cloke, A Brief History of Civil Liberties Protest Movements in Berkeley – From TASC to SLATE to FSM (1957-1965) (Santa Monica, CA: CDR Press, 1994).
• Jo Freeman, At Berkeley in the 60s: The Education of an Activist, 1961-1965 (Bloomington: Indiana University Press, 2004). ISBN 0-253-21622-2
• David Lance Goines, The Free Speech Movement: Coming of Age in the 1960s (Berkeley, CA: Ten Speed Press, 1993), pp. 65-82. ISBN 0-89815-535-5
• David Horowitz, Student (New York: Ballantine Books, 1962), pp. 17-22.
• Mike Miller, “Organizing for Social Change: What We Did Right, What Went Wrong, How We Can Overcome,” Social Policy, Winter 2000, pp. 4-12.
• Bruce Payne, David Walls, and Jerry Berman, "Theodicy of 1984: The Philosophy of Clark Kerr," The Activist (Spring 1962); reprinted in The New Student Left: An Anthology, ed. Mitchell Cohen and Dennis Hale (Boston: Beacon Press, 1966), pp. 226-236.
• W. J. Rorabaugh, Berkeley at War: The 1960s (New York, Oxford University Press, 1989), pp. 15-16. ISBN 0-19-505877-1
• “UC Ousts Liberal Club – As Freedom Is Defended,” San Francisco News-Call Bulletin, June 14, 1961, p. 1.
• Seymour Martin Lipset and Sheldon S. Wolin, eds., The Berkeley Student Revolt: Facts and Interpretations (Garden City, NY: Doubleday/Anchor, 1965).
• Charles Kaiser, “Radical Group of the ‘50s and ‘60s Plans a Rather Traditional Affair,” The Wall Street Journal, June 19, 1984, p. 33.
• Gerald C. Lubenow, “A SLATE Reunion: The Way They Were,” Newsweek, July 16, 1984.

External links

• SLATE Archives
• About SLATE
• Free Speech Movement Digital Archive
• FSM-A the Free Speech Movement Archives